Acrylic sol composition

ABSTRACT

An acrylic sol composition comprising (a) acrylic polymer fine particles, (b) blocked polyurethane, (c) a polyamine compound containing at least one modification product derived from a polyether polyamine compound represented by formula (I):  
                 
wherein X represents a residue of a di- to hexahydric polyol with m hydroxyl groups removed therefrom; A represents an alkylene group having 2 to 4 carbon atoms; B represents an alkylene group having 1 to 4 carbon atoms; m represents a number of 2 to 6; and n represents a number of 0 to 50; a plurality of A&#39;s, B&#39;s, and n&#39;s per molecule may be each the same or different, (d) a plasticizer, and (e) a filler. The composition generates neither hydrogen chloride nor dioxin when incinerated, exhibits high storage stability, cures at relatively low temperatures, and provides a coating film excellent in adhesion to a substrate, cold resistance, and strength.

TECHNICAL FIELD

This invention relates to an acrylic sol composition and, moreparticularly, to an acrylic sol composition free from generation ofhydrogen chloride gas and dioxin when incinerated, excellent in storagestability, curable at relatively low temperature, and capable ofproviding a coating film excellent in adhesion to a substrate, coldresistance, and strength.

BACKGROUND ART

Plastisol currently and widely used in industry is a composition with aliquid or glue-like consistency in which polymer particles havingspecifically controlled particle size and particle size distributiondispersed homogeneously in a plasticizer together with a filler.Plastisol applied to a substrate and given processing heat at a propertemperature forms a tough coating film.

Polymers generally used in plastisol include vinyl chloride homopolymersand vinyl chloride-based polymers such as vinyl chloride-vinyl acetatecopolymers. These polyvinyl chloride (hereinafter, “PVC”) plastisolshave excellent room-temperature, long-term storage stability and form asoft and durable coating film and are therefore widely used in thefields of coated steel plates, clothing, constructional materials, dailynecessities and miscellaneous goods, automobile parts, and so forth.

However, PVC plastisols decompose by heat or light to give off hydrogenchloride gas. Hydrogen chloride gas thus generated poses problems suchthat it supplies a source of ozone depleting substances, causes acidrain, and accelerates damage to incinerators when incinerated. Moreover,there is a danger of dioxin generation under some incinerationconditions. Therefore PVC plastisols are unfavorable to safety, health,and environmental conservation, and development of new plastisolsupplanting PVC plastisols has been awaited.

The patent document 1 proposes plastisol comprising an acrylate polymerand an organic plasticizer that can replace PVC plastisol, which hasturned out to be insufficient in storage stability and film-formingproperties.

The patent document 2 discloses PVC-free plastisol comprising a methylmethacrylate homo- or copolymer, a plasticizer, a filler, a blockedpolyisocyanate, and a polyamine. When processed at a relatively lowtemperature, however, the plastisol fails to form a coating film withsatisfactory properties on account of insufficient cure of the urethaneresin. In addition, when left to stand at around 35° C., the plastisolturns into a gel in one or two days.

The patent document 3 proposes acrylic sol comprising acrylic polymerfine particles, a blocked urethane resin, a solid hydrazine curingagent, a plasticizer, and a filler. The patent document 4 proposesacrylic sol for sound absorbing undercoating comprising acrylic polymerfine particles, a plasticizer, a filler, a blocked urethane resin, acuring agent, and a blowing agent. These acrylic sols, however, have adisadvantage, such as insufficient adhesion to a substrate orinsufficient flexibility particularly in low temperature.

Furthermore, the patent document 5 proposes a thermosetting compositioncomprising plastisol, a blocked urethane or blocked isocyanate, and alatent curing agent, the plastisol comprising core-shell type acrylicresin particles, a filler, and a plasticizer. The patent document 6discloses a thermosetting composition comprising plastisol, a blockedurethane or blocked isocyanate, and a latent curing agent, the plastisolcomprising acrylic resin particles, a filler, and a plasticizer. Thelatent curing agent is particulate solid at ambient temperature, has amelting point of 60° C. or higher, and is insoluble in the plasticizerat 40° C. or lower. These thermosetting compositions are stillunsatisfactory in viscosity stability and adhesion, however.

-   Patent document 1: JP-B-55-16177-   Patent document 2: JP-B-63-66861-   Patent document 3: JP-A-2001-329135-   Patent document 4: JP-A-2001-329208-   Patent document 5: WO01/88009A1-   Patent document 6: WO01/88011A1

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention:

The present invention has been completed in the light of the abovecircumstances. An object of the invention is to provide an acrylic solcomposition which does not generate hydrogen chloride or dioxin whenincinerated, exhibits high storage stability, cures at relatively lowtemperatures, and provides a coating film excellent in adhesion to asubstrate, cold resistance, and strength.

Means for Solving the Problems:

As a result of extensive investigations, the inventors of the presentinvention have found that an acrylic sol composition settling theabove-described problems can be obtained by incorporating a modifiedpolyoxyalkylene polyamine compound into an acrylic sol compositioncomprising acrylic polymer fine particles, blocked polyurethane, etc.and now reached the present invention.

The present invention provides an acrylic sol composition comprising (a)acrylic polymer fine particles, (b) blocked polyurethane, (c) apolyamine compound containing at least one modification product derivedfrom a polyether polyamine compound represented by formula (I) shownbelow, (d) a plasticizer, and (d) a filler.

wherein X represents a residue of a di- to hexahydric polyol having mhydroxyl groups removed therefrom; A represents an alkylene group having2 to 4 carbon atoms; B represents an alkylene group having 1 to 4 carbonatoms; m represents a number of 2 to 6; and n represents a number of 0to 50; a plurality of A's, B's, and n's per molecule may be each thesame or different.Best Mode for Carrying Out the Invention:

The acrylic sol composition of the present invention will be describedin detail with reference to its preferred embodiments.

The acrylic polymer fine particles (a) that can be used in the inventioninclude those commonly employed in acrylic sol compositions, such ashomo- and copolymers of monomers selected from alkyl acrylates and alkylmethacrylates. Specific examples of the monomers are methyl acrylate,ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate,isobutyl acrylate, sec-butyl acrylate, tert-butyl acrylate, cyclohexylacrylate, benzyl acrylate, methyl methacrylate, ethyl methacrylate,n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate,isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate,cyclohexyl methacrylate, and benzyl methacrylate.

Styrene, α-methylstyrene, methacrylic acid, acrylic acid, itaconic acid,and crotonic acid, etc. can be used as copolymerizable monomers.

Core-shell acrylic polymer fine particles composed of a core and anouter shell are preferred as component (a). Use of the core-shellacrylic polymer fine particles is advantageous in that the resultingacrylic sol composition exhibits further improved storage stability andis more inhibited from increasing the viscosity when applied and frombleeding after heat curing.

In using core-shell acrylic polymer fine particles as component (a), itis preferred that the core be formed of a polymer compatible with aplasticizer and the shell be formed of a polymer incompatible with theplasticizer. With the plasticizer-compatible core being covered with theplasticizer-incompatible polymer shell, the acrylic sol composition hasthe improved storage stability without increasing its viscosity duringstorage. Such a shell-forming polymer becomes compatible with theplasticizer on being heated to an appropriate temperature so that nobleeding occurs after heat cure.

The core preferably contains 50% by mass or more of at least one polymerselected from homo- and copolymers of a methacrylate monomer(s) such asn-butyl methacrylate, isobutyl methacrylate, and ethyl methacrylate. Bymaking the core of such a polymer having high compatibility with aplasticizer, bleeding after heat curing can be suppressed. In order toimpart flexibility to a coating film, in particular, it is stillpreferred that the core be made mainly of a butyl methacrylate-isobutylmethacrylate copolymer.

The shell preferably contains 50% by mass or more of at least onepolymer selected from homo- or copolymers of a methacrylate monomer(s)such as methyl methacrylate and benzyl methacrylate and copolymers ofthe methacrylate monomer and comonomers such as styrene. By making theshell of such a polymer having low compatibility with a plasticizer, theparticles bring about further improved storage stability of the acrylicsol composition, suppressing an increase in viscosity during storage. Tofurther ensure improvement in storage stability, the shell is stillpreferably made of a polymer mainly comprising a methyl methacrylatemonomer.

The ratio of the core-forming polymer to the shell-forming polymerpreferably ranges from 25/75 to 70/30 by mass. Particles having acore/shell ratio of less than 25/75 by part by weight are more likely tocause bleeding after heat cure than those having the above-recitedpreferred core/shell ratio. With a core/shell ratio exceeding 70/30 bypart by weight, it is more likely that the core is insufficientlycovered with the shell than with the above-recited preferred core/shellratio, which can adversely affect the storage stability.

The core-shell acrylic polymer fine particles that can be used in theacrylic sol composition of the invention include those described inJP-A-6-172734, JP-A-2001-329135, JP-A-2001-329208, and WO01/88009.

It is preferred for the acrylic polymer fine particles (a) to have aweight average molecular weight of 100,000 to several millions from thestandpoint of coating film strength and storage stability and to have anaverage particle size of 0.1 to 10 μm from the viewpoint ofdispersibility in a plasticizer and storage stability.

The blocked polyurethane that can be used in the invention as component(b) is one prepared by reacting a polyisocyanate with an α-polyol, suchas polyether polyol or polyester polyol, and blocking the resultingpolyurethane with a blocking agent.

The polyisocyanate includes propane 1,2-diisocyanate, 2,3-dimethylbutane2,3-diisocyanate, 2-methylpentane-2,4-diisocyanate,octane-3,6-diisocyanate, 3,3-dinitropentane-1,5-diisocyanate,octane-1,6-diisocyanate, 1,6-hexamethylene diisocyanate (HDI),trimethylhexamethylene diisocyanate, lysine diisocyanate, tolylenediisocyanate (TDI), xylylene diisocyanate, metatetramethylxylylenediisocyanate, isophorone diisocyanate (or3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate), 1,3- or1,4-bis(isocyanatomethyl)cyclohexane, diphenylmethane-4,4′-diisocyanate(MDI), dicyclohexylmethane 4,4′-diisocyanate (or hydrogenated MDI),hydrogenated tolylene diisocyanate, and mixtures thereof. Thesepolyisocyanate compounds may take an isocyanurate (trimer) form.

An isocyanurate form of the polyisocyanate can be obtained bypolymerizing the polyisocyanate in an inert solvent (e.g., methylacetate, ethyl acetate, butyl acetate, methyl ethyl ketone or dioxane)or a plasticizer (such as a phthalic ester, e.g., diethyl phthalate,dibutyl phthalate, di-2-ethylhexyl phthalate, a mixed alkyl phthalatehaving 7 to 11 carbon atoms in the alkyl moiety (represented as C₇-C₁₁),butylbenzyl phthalate or hexanolbenzyl phthalate; a phosphoric ester,e.g., tricresyl phosphate or triphenyl phosphate; an adipic ester, e.g.,di-2-ethylhexyl adipate; or a trimellitic ester, e.g., a C₇-C₁₁ mixedalkyl trimellitate) in the presence of a known catalyst (e.g., tertiaryamines, quaternary ammonium compounds, Mannich bases, fatty acid alkalimetal salts or alcoholates) in a known manner. It is desirable that apolymerization product system obtained by using a highly volatilesolvent be finally subjected to solvent replacement with an appropriatehigh-boiling solvent, such as a plasticizer.

Of these polyisocyanates at least one compound selected from1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI),and dicyclohexylmethane-4,4′-diisocyanate (hydrogenated MDI) ispreferred for obtaining an acrylic sol composition excellent in storagestability.

The polyether polyol that can be used with the polyisocyanate in thepreparation of the blocked polyurethane (b) preferably includespolyalkylene glycol (molecular weight: ca. 100 to 5500) adducts ofpolyhydric alcohols.

The polyhydric alcohols include aliphatic dihydric alcohols, such asethylene glycol, propylene glycol, 1,4-butylene glycol, and neopentaneglycol; trihydric alcohols, such as glycerol, trihydroxyisobutane,1,2,3-butanetriol, 1,2,3-pentanetriol, 2-methyl-1,2,3-propanetriol,2-methyl-2,3,4-butanetriol, 2-ethyl-1,2,3-butanetriol,2,3,4-pentanetriol, 2,3,4-hexanetriol, 4-propyl-3,4,5-heptanetriol,2,4-dimethyl-2,3,4-pentanetriol, pentamethylglycerol, pentaglycerol,1,2,4-butanetriol, 1,2,4-pentanetriol, and trimethylolpropane;tetrahydric alcohols, such as erythritol, pentaerythritol,1,2,3,4-pentanetetrol, 2,3,4,5-hexanetetrol, 1,2,3,5-pentanetetraol, and1,3,4,5-hexanetetrol; pentahydric alcohols, such as ribitol, arabinitol,and xylitol; and hexahydric alcohols, such as glucitol, mannitol, andiditol. Of the polyhydric alcohols preferred are di-, tri- andtetrahydric alcohols, with propylene glycol and glycerol beingparticularly preferred.

The polyether polyols can be prepared by adding an alkylene oxide having2 to 4 carbon atoms to such a polyhydric alcohol to give a desiredmolecular weight in a usual manner. The alkylene oxide having 2 to 4carbon atoms includes ethylene oxide, propylene oxide, and butyleneoxide, with propylene oxide being preferred.

The polyester polyols that can be used with the polyisocyanate in thepreparation of the blocked polyurethane (b) include cnnventionally knownpolyesters prepared from, for example, polycarboxylic acids andpolyhydric alcohols and polyesters obtained from lactams.

The polycarboxylic acids include benzenetricarboxylic acid, adipic acid,succinic acid, suberic acid, sebacic acid, oxalic acid, methyladipicacid, glutaric acid, pimelic acid, azelaic acid, phthalic acid,terephthalic acid, isophthalic acid, thiodipropionic acid, maleic acid,fumaric acid, citraconic acid, itaconic acid, and other appropriate likeones.

The polyhydric alcohols include ethylene glycol, propylene glycol,1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol,bis(hydroxymethylchlorohexane), diethylene glycol, 2,2-dimethylpropyleneglycol, 1,3,6-hexanetriol, trimethylolpropane, pentaerythritol,glucitol, glycerol, and other appropriate like ones. In addition,polyhydroxy compounds, such as polytetramethylene glycol andpolycaprolactone glycol, are also usable.

Of the above-recited α-polyols preferred are the polyether polyols,especially those having at least trifuncitonality. In particular, use ofglycerol tris(polypropylene glycol) results in an acrylic solcomposition excellent in adhesion to a substrate.

The polyurethane composing the blocked polyurethane (b) is obtained by,for example, allowing a polyhydroxy compound, such as theabove-described polyether polyol and/or polyester polyol or its mixturewith a hydroxy-containing glyceride, e.g., castor oil, to react with theaforementioned polyisocyanate.

In the preparation of the polyurethane, a molar ratio of thepolyisocyanate to the polyhydroxy compound, e.g., an α-polyol, isusually 1.5 to 3.5/1, preferably 2.0 to 3.5/1. The NCO content of theprepolymer (polyurethane) is usually 1% to 20%, preferably 1% and 10%.

The polyurethane can be obtained in a common method. The reactiontemperature is usually 40° to 140° C., preferably 60° to 130° C. Thereaction can be carried out using a known catalyst for acceleratingurethane polymerization, such as an organometallic compound, e.g.,dibutyltin dilaurate, tin (II) octoate, stannous octoate, lead octylate,lead naphthenate, and zinc octylate, or a tertiary amine compound, e.g.,triethylenediamine or triethylamine.

The blocked polyurethane (b) is obtained by blocking the above-mentionedpolyurethane with a blocking agent. The blocking agent includes activemethylene compounds, such as malonic diesters (e.g., diethyl malonate),acetylacetone, and acetoacetic esters (e.g., ethyl acetoacetate); oximecompounds, such as acetoxime, methyl ethyl ketoxime (MEK oxime), andmethyl isobutyl ketoxime (MIBK oxime); monohydric alcohols, such asmethyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, heptylalcohol, hexyl alcohol, octyl alcohol, 2-ethylhexyl alcohol, isononylalcohol, stearyl alcohol, and their isomers; glycol derivatives, such asmethyl glycol, ethyl glycol, ethyl diglycol, ethyl triglycol, butylglycol, and butyl diglycol; and amine compounds, such asdicyclohexylamine.

The blocking reaction to obtain the blocked polyurethane (b) isperformed in a known manner. The blocking agent is used in an amountusually of from 1 to 2 equivalents, preferably 1.00 to 1.5 equivalents,per free isocyanate group.

While the blocking of the polyurethane is commonly effected by addingthe blocking agent to the polyurethane polymerization system in thefinal stage of the polymerization, the blocked polyurethane (b) may beobtained by adding the blocking agent in an arbitrary stage of thepolymerization.

The blocking agent can be added either at the end of or in the initialstage of polymerization or, part of the blocking agent may be added inthe initial stage of polymerization, and the rest at the end of thepolymerization. Preferably, the blocking agent is added at the end ofthe polymerization. The isocyanate content (%), which is determined by,for example, the method described in Polyurethane, Maki Shoten, 1960,21, can be used as an indication of the end point of polymerization. Thereaction temperature at which the blocking agent is added is usually 50°to 150° C., preferably 60° to 120° C. The reaction time is usually about1 to 7 hours. It is possible to accelerate the reaction by addition ofthe aforesaid known catalyst for urethane polymerization. In effectingthe reaction, an arbitrary amount of the plasticizer described later canbe added to the reaction system.

The acrylic sol composition of the present invention preferably containsthe acrylic polymer fine particles (a) and the blocked polyurethane (b)at an (a) to (b) ratio of 90/10 to 15/85, still preferably 90/10 to50/50, by mass. When the amount of the blocked polyurethane (b) is lessthan 10 parts by mass for 90 parts by mass of the acrylic polymer fmeparticles (a), the coating film of the acrylic sol composition tends tobe insufficient in adhesion to a substrate, cold resistance, andstrength as compared with that of the acrylic sol composition having theabove-recited preferred (a) to (b) ratio. When the amount of the blockedpolyurethane (b) is more than 85 parts by mass for 15 parts by mass ofthe acrylic polymer fine particles (a), the acrylic sol compositiontends to have an increased viscosity, which can impair the workabilityin applying the composition, as compared with that having theabove-recited preferred (a) to (b) ratio.

The polyamine compound as component (c) is then described. In formula(I), X represents a residue of a polyol with m hydrbxyl groups removedtherefrom. The polyol that provides the residue X includes ethyleneglycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol,1,4-butanediol, 1,6-hexanediol, neopentyl glycol, benzenedimethanol,cyclohexanedimethanol, glycerol, trimethylolethane, trimethylolpropane,pentaerythritol, diglycerol, ditrimethylolpropane, glucitol, mannitol,and dipentaerythritol. Di- or trihydric polyols are preferred of them.The alkylene group having 2 to 4 carbon atoms as represented by Aincludes ethylene, 1,2-propylene, 1,3-propylene, 1,2-butylene,1,3-butylene, and 1,4-butylene. Ethylene or propylene is preferred ofthem. The alkylene group having 1 to 4 carbon atoms as represented by Bincludes methylene, ethylene, 1,2-propylene, 1,3-propylene,1,2-butylene, 1,3-butylene, and 1,4-butylene. Ethylene or propylene ispreferred of them. m is preferably 2 or 3, and n is preferably 0 to 10.

The polyether polyamine compound represented by formula (I) is known. Itis synthesized by, for example, adding an alkylene oxide, e.g., ethyleneoxide or propylene oxide, to a polyol having the residue X and aminatingthe terminal hydroxyl groups or adding acrylonitrile to the terminalhydroxyl groups followed by reduction to convert the nitrile groups toamino groups.

Typical examples of the polyether polyamine compounds of formula (I)

wherein n1 represents a number of 3 to 100; n2 and n3 each represent anumber of 1 to 50; and n4, n5, and n6 each represent a number of 0 to50.

Commercially available products of these compounds include Jeffamine Dseries (D-230, D-400, D-2000, and D-4000), Jeffamine ED series (ED-600and ED-2003), and Jeffamine T series (T-403, T-3000, and T-5000), allavailable from Heinz Japan Ltd.).

A modification product of the above-described polyether amine compound,which can be used as the polyamine compound (c) in the presentinvention, is the polyether amine compound of formula (I) having a partof the N-H groups thereof modified to have reduced reactivity. Such amodification product includes epoxy adducts, acrylate adducts, polyamideadducts and Mannich reaction products of the polyether polyaminecompounds of formula (I).

Of these modification products, epoxy adducts or acrylate adducts of thepolyether polyamine compounds of formula (I) are preferred; for theyprovide an acrylic sol composition with excellent storage stability.

Epoxy compounds (polyglycidyl compounds) providing the epoxy adductsinclude polyglycidyl ether compounds of mononuclear polyhydric phenolcompounds, such as hydroquinone, resorcin, pyrocatechol, andphloroglucinol; polyglycidyl ether compounds of polynuclear polyhydricphenol compounds, such as dihydroxynaphthalene, biphenol,methylenebisphenol (or bisphenol F), methylenebis(orthocresol),ethylidenebisphenol, isopropylidenebisphenol (or biphenol A),isopropylidenebis(orthocresol), tetrabromobisphenol A,1,3-bis(4-hydroxycumylbenzene), 1,4-bis(4-hydroxycumylbenzene),1,1,3-tris(4-hydroxyphenyl)butane, 1,1,2,2-tetra(4-hydroxyphenyl)ethane,thiobisphenol, sulfobisphenol, oxybisphenol, phenol novolak, orthocresolnovolak, ethylphenol novolak, butylphenol novolak, octylphenol novolak,resorcin novolak, bisphenol A novolak, bisphenol F novolak, andterpenediphenol; polyglycidyl ether compounds of ethylene oxide and/orpropylene oxide adducts of the above-enumerated mononuclear orpolynuclear polyhydric phenol compounds; polyglycidyl ether compounds ofhydrogenation products of the above-enumerated mononuclear polyhydricphenol compounds; polyglycidyl ethers of polyhydric alcohols, such asethylene glycol, propylene glycol, butylene glycol, hexanediol,polyglycol, thiodiglycol, glycerol, trimethylolpropane, pentaerythritol,glucitol, a bisphenol A-ethylene oxide adduct, anddicyclopentadienedimethanol; homo- or copolymers of glycidyl esters ofaliphatic, aromatic or alicyclic polybasic acids, e.g., maleic acid,fumaric acid, itaconic acid, succinic acid, glutaric acid, suberic acid,adipic acid, azelaic acid, sebacic acid, dimer acid, trimer acid,phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid,trimesic acid, pyromellitic acid, tetrahydrophthalic acid,hexahydrophthalic acid, and endomethylenetetrahydrophthalic acid, orglycidyl methacrylate; epoxy compounds having a glycidylamino group,such as N,N-diglycidylaniline andbis(4-(N-methyl-N-glycidylamino)phenyl)methane; epoxidized cyclic olefincompounds, such as vinylcyclohexene diepoxide, dicyclopentanedienediepoxide, 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate,3,4-epoxy-6-methylcyclohexylmethyl-6-methylcyclohexanecarboxylate, andbis(3,4-epoxy-6-methylcyclohexylmethyl) adipate; epoxidized conjugateddiene polymers, such as an epoxidized polybutadiene and an epoxidizedstyrene-butadiene copolymer; and heterocyclic compounds, such astriglycidyl isocyanurate. The epoxy compound may be a compoundinternally crosslinked with an isocyanate-terminated prepolymer. Of therecited epoxy compounds preferred are bisphenol A or F epoxy resins.

The method of preparing an epoxy adduct from the polyether polyaminecompound of formula (I) and the epoxy compound is not particularlylimited. For example, the epoxy adduct can easily be obtained by using0.3 to 1.2 equivalents of the epoxy compound per mole of the polyetherpolyamine compound and conducting the addition reaction at 100° to 200°C. for several minutes to several hours, if needed, in a solvent.

Acrylic compounds that provide the acrylate adducts include methylacrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methylmethacrylate, ethyl methacrylate, propyl methacrylate, butylmethacrylate, and acrylonitrile, with alkyl acrylates being preferred.

The method of preparing an acrylate adduct from the polyether polyaminecompound of formula (I) and the acrylic compound is not particularlylimited. For example, the acrylate adduct can easily be obtained byusing 0.3 to 1.2 mol of the acrylic compound per mole of the polyetherpolyamine compound and performing the reaction (dealcoholation) at 100°to 300° C. for several minutes to several hours in the presence of acatalyst, e.g., p-toluenesulfonic acid, if desired, in a solvent.

The plastisol composition of the invention may contain a polyaminecompound other than the polyether polyamine compound (I) modificationproduct as part of the polyamine compound (c).

Examples of the other useful polyamine compounds include aliphaticpolyamines, such as ethylenediamine, diethylenetriamine,triethylenetetramine, and tetraethylenepentamine; alicyclic polyamines,such as isophoronediamine, menthenediamine,bis(4-amino-3-methyldicyclohexyl)methane, diaminodicyclohexylmethane,bis(aminomethyl)cyclohexane, N-aminoethylpiperazine, and3,9-bis(3-aminopropyl)-2,4,8,10-tetraoxaspiro(5.5)undecane; mononuclearpolyamines, such as m-phenylenediamine, p-phenylenediamine,tolylene-2,4-diamine, tolylene-2,6-diamine, mesitylene-2,4-diamine,mesitylene-2,6-diamine, 3,5-diethyltolylene-2,4-diamine, and3,5-diethyltolylene-2,6-diamine; aromatic polyamines, such asbiphenylenediamine, 4,4-diaminodiphenylmethane, 2,5-naphthylenediamine,and 2,6-naphthylenediamine; and modification compounds derived from theabove-recited polyamine compound, such as graft-modified polyaminesobtained by glycidyl ether addition and Mannich-modified polyaminesobtained by modification with phenols and aldehydes.

The modification product of the polyether polyamine compound (I) as thepolyamine compound (c) is preferably used in an amount of 0.01 to 10parts by mass, still preferably 0.05 to 5 parts by mass, per 100 partsby mass of the acrylic polymer fine particles (a). The other polyaminecompound(s) can be used in an arbitrary amount up to 10 parts by massper 100 parts by mass of the acrylic polymer fine particles (a).

The plasticizer that can be used in the invention as component (d)includes those conventionally employed in PVC plastisol, such asphthalic acid plasticizers, e.g., diisononyl phthalate, di(2-ethylhexyl)phthalate, diisodecyl phthalate, and butylbenzyl phthalate; fatty acidester plasticizers, e.g., di(2-ethylhexyl) adipate, di-n-decyl adipate,di(2-ethylhexyl) azelate, dibutyl sebacate, and di(2-ethylhexyl)sebacate; phosphoric ester plasticizers, e.g., tributyl phosphate,tri(2-ethylhexyl) phosphate, and 2-ethylhexyldiphenyl phosphate; epoxyplasticizers, e.g., epoxidized soybean oil; polyester plasticizers, andbenzoic acid plasticizers. These plasticizers can be used eitherindividually or as a combination of two or more thereof. It isparticularly preferred to use diisononyl phthalate in view of its lowprice and availability. From the aspect of coating film strength,workability in applying the composition and the like, the plasticizer(d) is preferably used in an amount of 50 to 500 parts by mass, stillpreferably 80 to 300 parts by mass, per 100 parts by mass of the acrylicpolymer fine particles (a).

The filler that can be used in the invention as component (e) includesthose commonly employed in plastisol, such as calcium carbonate, mica,talc, kaolin clay, silica, and barium sulfate. Fibrous fillers, such asglass fiber, wollastonite, alumina fiber, ceramic fiber, and variouswhiskers, are also useful. Calcium carbonate is particularly preferredbecause of its low price. From the viewpoint of coating film strength,cost, and the like, the filler (e) is preferably used in an amount of 50to 800 parts by mass, still preferably 80 to 500 parts by mass, per 100parts by mass of the acrylic polymer fine particles (a).

The acrylic sol composition of the invention can contain other additivesknown in the art, including colorants, antioxidants, blowing agents,diluents, and ultraviolet absorbers, in addition to the components (a)to (e). Useful colorants include inorganic pigments, such as titaniumdioxide and carbon black, and organic pigments, such as azo pigments andphthalocyanine pigments. Useful antioxidants include phenol antioxidantsand amine antioxidants. The blowing agents that can be used includethose which generate gas on heating, such as azo blowing agents, e.g.,azodicarbonamide and azobisformamide. Useful diluents include solventssuch as xylene and mineral turpentine. Useful ultraviolet absorbersinclude benzotriazole derivatives.

The acrylic sol composition of the invention can be prepared by anymethod conventionally and commonly employed for plastisol preparation.For example, the acrylic sol composition of the invention is prepared bythoroughly mixing the acrylic polymer fine particles (a), the blockedpolyurethane (b), the polyamine compound (c), the plasticizer (d), thefiller (e), and, if desired, other additives by stirring in a knownmixing machine. Useful mixing machines include a planetary mixer, akneader, a grain mill, and a roll.

The acrylic sol composition of the invention can be applied byconventional known coating methods including brush coating, rollercoating, air spraying, and airless spraying. The applied acrylic solcomposition is heated to form a coating film. Heating is carried out inan ordinary manner, for example, using a hot air circulating dryingoven.

The acrylic sol composition of the present invention is suited for useas coatings, inks, adhesives, pressure-sensitive adhesives, sealingagents, and so forth. It is also applicable to molded articles includingdaily miscellaneous goods, toys, industrial parts, and electrical parts.Application to paper, cloth, etc. provides artificial leather, rugs,wallpaper, clothing materials, waterproof sheets, etc. Application to ametal plate provides an anticorrosive metal plate.

EXAMPLES

The acrylic sol composition of the present invention will now beillustrated more concretely by way of Examples.

Preparation Example 1

Preparation of Blocked Polyurethane (BU-1)

In a reaction vessel were charged 400 g of diisononyl phthalate, 472 gof glycerol tris(polypropylene glycol) (molecular weight: 4000) and0.025 g of dibutyltin laurate and subjected to dehydration reaction at100° to 110° C. under reduced pressure of 30 mmHg for 1 hour. Thereaction mixture was cooled to 60° C., and 95 g ofdicyclohexylmethane-4,4′-diisocyanate (hydrogenated MDI) was addedthereto, followed by allowing the mixture to react in a nitrogenatmosphere at 60° to 70° C. for 3 hours. The reaction system was cooledto 60° C., and 33 g of methyl ethyl ketoxime was added thereto dropwise,followed by aging at 80° to 90° C. for 1 hour, and followed bydegasification at 100° to 110° C. under 30 mmHg for 1 hour.

After confirming complete disappearance of the NCO absorption at 2660cm⁻¹ in the IR spectrum, blocked polyurethane, designated BU-1, wasobtained.

Preparation Example 2

Preparation of Blocked Polyurethane (BU-2)

In a reaction vessel were charged 400 g of diisononyl phthalate, 499 gof glycerol tris(polypropylene glycol) (molecular weight: 4000) and0.025 g of dibutyltin laurate and subjected to dehydration reaction at100° to 110° C. under reduced pressure of 30 mmHg for 1 hour. Thereaction mixture was cooled to 60° C., and 65 g of 1,6-hexamethylenediisocyanate was added thereto, followed by allowing the mixture toreact in a nitrogen atmosphere at 60° to 70° C. for 3 hours. Thereaction system was cooled to 60° C., and 33 g of methyl ethyl ketoximewas added thereto dropwise, followed by aging at 80° to 90° C. for 1hour, and followed by degasification at 100° to 110° C. under 30 mmHgfor 1 hour.

After confirming complete disappearance of the NCO absorption at 2660cm⁻¹ in the IR spectrum, blocked polyurethane, designated BU-2, wasobtained.

Preparation Example 3

Preparation of Blocked Polyurethane (BU-3)

In a reaction vessel were charged 400 g of diisononyl phthalate, 482 gof glycerol tris(polypropylene glycol) (molecular weight: 4000), and0.025 g of dibutyltin laurate and subjected to dehydration reaction at100° to 110° C. under reduced pressure of 30 mmHg for 1 hour. Thereaction mixture was cooled to 60° C., and 84 g of isophoronediisocyanate was added thereto, followed by allowing the mixture toreact in a nitrogen atmosphere at 60° to 70° C. for 3 hours. Thereaction system was cooled to 60° C., and 33 g of methyl ethyl ketoximewas added thereto dropwise, followed by aging at 80° to 90° C. for 1hour, and followed by degasification at 100° to 110° C. under 30 mmHgfor 1 hour.

After confirming complete disappearance of the NCO absorption at 2660cm⁻¹ in the IR spectrum, blocked polyurethane, designated BU-3, wasobtained.

Preparation Example 1

Preparation of Blocked Isocyanate

In a reaction vessel was put 600 g of diisononyl phthalate anddehydrated at 100° to 110° C. under reduced pressure of 30 mmHg or lessfor 1 hour. Coronate 2030 (tolylene diisocyanate in nurate form,available from Nippon Polyurethane Industry Co., Ltd.) was addedthereto, and the mixture was heated at 130° to 140° C. under 30 mmHg orless for 4 hours to remove butyl acetate. ε-Caprolactam and dibutyltinlaurate were added to the reaction mixture, and the mixture was allowedto react at 130° to 140° C. and 4 hours.

After confirming complete disappearance of the NCO absorption at 2660cm⁻¹ in the IR spectrum, blocked isocyanate, designated BI-1, wasobtained.

Preparation Example 4

Preparation of Modified Polyamine (PA-1)

In a reaction vessel were put 183 g of isophoronediamine and 200 g oftoluene and heated to 80° C. To the solution was added in portion 218 gof Adeka Resin EP-4100E (bisphenol A epoxy resin from Asahi Denka Co.,Ltd.; epoxy equivalent: 190), followed by aging at 90° to 100° C. for 2hours. To the mixture was added 600 g of Jeffamine T-403 (polyetherpolyamine, from Heinz). The mixture was heated up to 120° C., andnitrogen was blown therein to remove toluene. The reaction mixture wasfurther heated at 120° to 130° C. under reduced pressure of 30 mmHg orless for 2 hours to give modified polyamine PA-1.

Preparation Example 5

Preparation of Modified Polyamine (PA-2)

In a reaction vessel were charged 300 g of diisononyl phthalate and 526g of Jeffamine T-403 and heated to 80° C. To the mixture was added inportion 174 g of Adeka Resin EP-4100E (bisphenol A epoxy resin fromAsahi Denka Co., Ltd.; epoxy equivalent: 190), followed by aging at 80°to 90° C. for 2 hours to give modified polyamine PA-2.

Preparation Example 6

Preparation of Modified Polyamine (PA-3)

In a reaction vessel were put 895 g of Jeffamine D-230 and 1 g ofp-toluenesulfonic acid and heated up to 80° C. To the mixture was addeddropwise 167 g of methyl acrylate, followed by aging at 80° to 90° C.for 1 hour. The reaction mixture was heated at 180° to 190° C. for 2hours to remove methanol, and the residue was heated at 180° to 190° C.under reduced pressure of 30 mmHg or less for 1 hour to obtain modifiedpolyamine PA-3.

Comparative Preparation Example 2

Preparation of Modified Polyamine (HPA-1)

A mixture of 146 g of triethylenetetramine and 295 g of dimer acid wasallowed to react at 180° to 190° C. under atmospheric pressure for 2hours for dehydration and then at 180° to 190° C. under reduced pressureof 30 mmHg or lower for 2 hours to give modified polyamine HPA-1.

Examples 1 to 7 and Comparative Examples 1 to 5

Acrylic polymer fine particles were compounded with the blockedpolyurethane and the modified polyamine obtained in Preparation Examplesand Comparative Preparation Examples and other components according tothe formulations shown in Tables 1 and 2 below and dispersively mixed ina kneader to obtain acrylic sol compositions of Examples 1 to 7 andComparative Examples 1 to 5.

The acrylic sol compositions of Examples 1 to 7 and Comparative Examples1 to 5 were evaluated for viscosity stability, adhesion, colorlessness,and film strength in accordance with the following methods. The resultsobtained are shown in Tables 1 and 2.

(1) Viscosity Stability

The initial viscosity of the acrylic sol composition at 20° C. wasmeasured with a Brookfield viscometer. The acrylic sol composition wasthen put in a closed container and maintained at 35° C. for 10 days.After cooling to 20° C., the viscosity was measured again to obtain apercent viscosity change from the initial viscosity. A compositionshowing a viscosity change within 50% was rated “good”, and one showinga viscosity change of 50% or greater “poor”.

(2) Adhesion

The acrylic sol composition was applied to one end of anelectrodeposition-coated steel plate of 25 mm in width, 100 mm in lengthand 1.0 mm in thickness. That end of the plate was press bonded with anend of another plate with a spacer therebetween to have the jointthickness set at 3 mm. In this state, the joint was baked at 130° C. or180° C. each for 30 minutes, and the spacer was removed. The two plateswere pulled apart at a speed of 50 mm/min in a shear direction toobserve the failure of the joint. A cohesive failure was rated “good”,and an interfacial failure “poor”.

(3) Colorlessness

The acrylic sol composition having been baked at 130° C. or 180° C. eachfor 30 minutes was observed with the naked eye, and the state ofcoloration was rated “good” (little coloration), “fair” (coloration) or“poor” (noticeable coloration).

(4) Coating Film Strength

The acrylic sol composition was applied on a separable plate to athickness of 2 mm and baked at 130° C. for 30 minutes. The film waspunched into a dumbbell specimen (JIS, No. 2), which was pulled at aspeed of 50 mm/min at 23° C. to measure breaking strength (MPa) andelongation (%). TABLE 1 Example 1 2 3 4 5 6 7 Formulation (part bymass): AR*¹ 27 27 27 27 27 27 27 BU-1 (Prepn. Ex. 1) 9 9 9 9 9 BU-2(Prepn. Ex. 2) 9 BU-3 (Prepn. Ex. 3) 9 BI-1 (Compara. Prepn. Ex. 1) PA-1(Prepn. Ex. 4) 1 1 1 1 1 PA-2 (Prepn. Ex. 5) 1 PA-3 (Prepn. Ex. 6) 1HPA-1 (Compara. Prepn. Ex. 2) DINP*² 27 38 27 27 27 27 27 Calciumcarbonate 13.5 13.5 4.5 13.5 13.5 13.5 13.5 Surface-treated calciumcarbonate*³ 13.5 13.5 22.5 13.5 13.5 13.5 13.5 MSP*⁴ 9 9 9 9 9 9 Test onperformance properties: Viscosity stability good good good good goodgood good Adhesion 130° C. × 30 min good good good good good good good180° C. × 30 min good good good good good good good Colorlessness 130°C. × 30 min good good good good good good good 180° C. × 30 min goodgood good good good good good Film strength Breaking strength (MPa) 2.422.08 3.75 2.08 2.33 2.05 2.09 Elongation (%) 520 610 292 480 550 560 530*¹Core-shell acrylic polymer fine particles having a core mainly made ofbutyl methacrylate-isobutyl methacrylate copolymer and a shell mainlymade of methyl methacrylate polymer.*²Diisononyl phthalate*³Calcium carbonate surface treated with stearic acid*⁴Mineral spirit

TABLE 2 Comparative Example 1 2 3 4 5 Formulation (part by mass): AR 2727 27 27 27 BU-1 9 10 BU-2 BU-3 BI-1 10 9 PA-1 1 PA-2 PA-3 HPA-1 1 DINP27 27 27 27 27 Calcium carbonate 13.5 13.5 13.5 13.5 13.5Surface-treated calcium carbonate 13.5 13.5 22.5 13.5 13.5 MSP 9 9 9 9 9Test on performance properties: Viscosity stability good good poor goodpoor Adhesion 130° C. × 30 min poor poor good poor good 180° C. × 30 minpoor poor good poor poor Colorlessness 130° C. × 30 min good good fairgood good 180° C. × 30 min good good poor good good Film strengthBreaking strength (MPa) 1.4 1.23 2.97 1.65 1.07 Elongation (%) 370 335570 654 311

As is apparent from Table 2, the coating film of the acrylic solcomposition consisting of the acrylic polymer fine particles,plasticizer and filler (Comparative Example 1) has insufficient adhesionand is utterly insufficient in strength. Addition of the blockedisocyanate to the composition of Comparative Example 1 (ComparativeExample 2) brings about no improvement on adhesion or strength of thecoating film. Addition of the blocked polyurethane (Comparative Example4) results in slight improvement in coating film strength but bringsabout no improvement on adhesion. Where the blocked polyurethane and thepolyamine compound other than the specific polyamine compound accordingto the invention are added (Comparative Example 3), althoughimprovements in adhesion and strength of the coating film are seen, thestorage stability markedly reduces, and the coating film undergoescoloration. Where the blocked isocyanate and the specific amine compoundof the invention are added (Comparative Example 5), the storagestability markedly reduces with no improvement in coating film strength,and the effect in improving the adhesion of the coating film is verysmall.

In contrast, as can be seen from Table 1, the acrylic sol compositionsconsisting of the acrylic polymer fine particles, blocked polyurethane,specific polyether polyamine modification product, plasticizer, andfiller are superior in storage stability stability and capability ofproviding a coating film with high adhesion and toughness.

INDUSTRIAL APPLICABILITY

The acrylic sol composition according to the present invention generatesneither hydrogen chloride gas nor dioxin when incinerated, exhibits highstorage stability, cures at relatively low temperatures, and provides acoating film excellent in adhesion to a substrate, cold resistance, andstrength. The acrylic sol composition is therefore useful in broadapplications including sealing compounds, coatings, and dailynecessitates.

1. An acrylic sol composition comprising, (a) acrylic polymer fineparticles, (b) blocked polyurethane, (c) a polyamine compound containingat least one modification product derived from a polyether polyaminecompound represented by formula (I):

wherein X represents a residue of a di- to hexahydric polyol having mhydroxyl groups removed therefrom; A represents an alkylene group having2 to 4 carbon atoms; B represents an alkylene group having 1 to 4 carbonatoms; m represents a number of 2 to 6; and n represents a number of 0to 50; a plurality of A's, B's, and n's per molecule may be each thesame or different, (d) a plasticizer, and (e) a filler.
 2. The acrylicsol composition according to claim 1, wherein the acrylic polymer fineparticles (a) and the blocked polyurethane (b) have a mass ratio (a)/(b)of 90/10 to 15/85.
 3. The acrylic sol composition according to claim 1,wherein the acrylic polymer fine particles (a) have a core-shellstructure comprising a core and a shell.
 4. The acrylic sol compositionaccording to claim 1, wherein the blocked polyurethane(b) is oneobtained from a polyether polyol and a diisocyanate.
 5. The acrylic solcomposition according to claim 4, wherein the polyether polyol is atleast trifunctional.
 6. The acrylic sol composition according to claim5, wherein the at least trifunctional polyether polyol is glyceroltris(polypropylene glycol).
 7. The acrylic sol composition according toclaim 4, wherein the diisocyanate is at least one compound selected fromthe group consisting of 1,6-hexamethylene diisocyanate, isophoronediisocyanate, and dicyclohexylmethane-4,4′-diisocyanate.
 8. The acrylicsol composition according to claim 1, wherein the modification productof the polyether polyamine compound represented by formula (I) is anepoxy adduct or an alkyl acrylate adduct.
 9. The acrylic sol compositionaccording to claim 8, wherein the epoxy adduct is one obtained by usinga bisphenol A or F epoxy resin.